Resilient mount



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RESILIENT MOUNT Filed March 27. 1944 DEF'LECT/o/v i INVENToR ATTORNEY teristics,l

Vatented June 5, y1945 UNITED STATES linria NT` ori-ica RESILIENT MOUNT Robert Elsbre Gonton, East Hartford, Conn., assignor to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Application March 27, 1944, serial No. 528,225

f' proved engine suspension means for connecting an engine to its support including resilient vibra- .tion controlling means having a low spring rate at normal operating load, with as little deflection asl possible in going from zero load to operating load, and having a sharply increasing spring rate above normal operating load to limit the deilection in this range.

A further object of the invention is to provide a resilient connecting means of the above type utilizing two springs each having a different loaddefleetion characteristic -and so arranged as to subject both to equal load throughout the operating range and to divide the deflection between them inversely as their stiffnesses under each condition of loading.

l A still further object of the invention` is to provide a` connecting means including two resilient members having different load-deection characand arranged to reduce the total stiffness of the mount in compression over aportion of the load range.

A still further object-of the invention isto provide a resilient connection comprising two serially arranged resilient elements bonded together and subjected to identical loading. I

A yet further object is generally to improve the' construction and effectiveness of resilient engine mounts.

In the drawing, in which similar reference characters designate similar partsin the several views,V one embodiment of the invention is illustrated for purposes ofdisclosing vthe invention.

In the drawing: 4

Fig. 1 is a sectional view through an engine 'y by aA plurality of angularly related struts l(not shown) in a Well known manner. y

The units AI4 are angularly spaced around the engine mounting ring and each comprises a number of separable parts including a member con- Y nected with the mounting ring, a member connected with the engine, and a core unit including resilient material which is interposed between said members. The engine connected member of the unit includes the pedestal I6 suitably connected to the engine by cap screws (not shown) and terminating in an upstanding lug I8 having an.

oblique passage 20. The ring connected member includes a two-part housing comprising a cup member 22 having at one side of its bottom a pair of laterally spaced lugs, one of which is shbwn at 24, throughwhich horizontally disposed cap screws 26 extend into a boss 28 which is secured las by welding to the ring. I2. A stud 30 projects horizontally fromthe other side of the bottom wall of cup member 22 through a radially inwardly directed lug 32 of a boss 34 welded to the inner periphery of ring I2, a nut 35 being threaded on the stud to secure the shoulder 36 at the .base of stud 30 against lug 32. A complemental cup-shaped cover member 38 forms a closure for cup member- 22, members 22 and 38 having their rims detachably connected b y screw-threads 4I). The cover member 38 has a dat bottom wall 42 provided with a central aperture 44 which is somewhat larger than passage` 20.

mount constructed in accordance withthe inven- K tion.

Fig. 2 is a graph illustrating the load deilection characteristics of each of the -two resilient elements comprising the core of the mount and also 'l the load deection characteristics of the assembled core.

aircraft, is supported on the mounting ring I2 by a plurality of vibration suppressing mounting The core unit comprises a mushroom shaped member having a head, or plate, portiorr 46 disposed approximately centrally in the ring supported housing member and a shank,` or stem, portion 48 which has a reduced portion 5U received in passage 20 and secured therein by a nut 52. The head portion 46 has resilient blocks of rubber 54 and 56 permanently secured to the opposite faces thereof, as by vulcanizing, these blocks havding axial passages 58 and 60 respectively therethrough. Further, these` locks 54 and 56 have heir remote annular fac s 62 and 64 dished, or 4pered inwardly toward their axis and have permanently bonded thereto, as by vul'canizing or cementing, Ythe dished plate springs 66 and 68 whichin their unstressed state, conform to the dished surfaces 62 and' 64; The plate spring 66 hasv a central annular aperture 'l0 "which is oi" the same diameter as aperture 56 in block 54 and platev spring 68 also has acentralannular aperunits one'ot which is generally indicated at I4.

The'ring I2 is rigidly connected to the aircrafty ture 1 2 which is oi. the same diameter as aperture in block 56 at thev dished face thereof and large enough to space the inner periphery of the ed to the periphery of the head portion t of the core member. These side walls may, however, be formed as concave or convex'suri'aces to vary the resilienceoi the blocks in compression to meet varying requirements.

Friction damping means are provided between the 'engine connected and ring connected inemwhich receive the outer peripheries of plate a resilient unit interposed between opposed surfaces bf said members including a rubber cushion and a conical plate spring bonded together in series.l

2. yn. ,flexible engine mount comprising a member secured to an engine to be supported and a member secured to a support for'the engine, and

' from the periphery of the plate springs Se and l@ bers for suppressing relative movement of these members by forces which place the resilient blocks of the core member in shear. The lug it is provided with an annular shoulder l@ concentric with the shank iid and provided with an annular bushing lill having a peripheral groove sup'- porting an annular plate 82 parallel but spaced g from the external hat bottom surface d2 oicup 3&3,A A disk of friction 'material 35 carried by 'plate 82 occupies this space and is pressed constantly against surface d2 by a disk spring B6 located between plate 82 and shoulder 'wand held in semi-compressed position by engagement of its inner periphery with vshoulder Eil and by erigagement of its outer periphery Ywith plate t2. Vibrational vforces acting in the direction of the major axis of lthe unit will place 'the rubber blocks hand SG and their attached plate springs Gti and St in compression. 'Furthen since these loads are transmittedthrougli the rubber blocks and plate springs in series, the blocks and springss will each be subjected to equal loadingiwhile the deiiection of each rubber block and its attached plate spring under load will Aalways be divided between them inversely 'las their stiffnesses.

Referring to Fig 2', it will be noted that when load is applied axially to a conical plate spring it has a very high spring rate initiallybut that its spring rate becomes very low as the spring l in its unloaded condition and bonded thereto,

approaches its flattened condition. The rubber block also has a very high spring rate which-is `substantiallycoi'istant throughout the range incicated. As a result of the nstruction above described, the -stiiiness in c mpression of the combined rubber and metal spring provides a very low spring rate in aportion oi the load deiiection curve and in accordance with this invention the metal and rubber springs are combined so that this portion of the curve will fall in the working load range vof the unit as indicated by y the lower curve in Fig." 2. It will be evident that Aas result of this construction-it has been made possible tov get the desired low spring rate throughout 'the gworking load range with a minimum oi deflection in going from zero load to the work- I ing load range, while also providing a sharply increasing spring rateabove this normal worki ingrange.

While one embodiment ofthe inventionV has ing drawing, it vwill be evident thatnumerous changes may be made in the construction and arrangement of the parts without departing from the scope of the invention as defined by the following claims:

l. A` flexible engine mountlcomprising a meinber secured to an engine to be supported and a. member secured to a support for the engine, and

, been described and illustratedl in the accompany'- a resilient unit interposed between opposed s ur-v faces of said members including a rubber cushion and a conical plate spring bonded together in their unstressed condition for absorbing forces exerted parallel to the axis of fiexure of said plate spring.

3. A ilexible engine mount comprising a member secured to an engine to be supported and a member secured to a support for the engine, and a-combined metal andirubber spring interposed between opposed surfaces of said menibe cluding a rubber cushion having a dished face confronting-one of said surfaces and a. dished plate spring conforming to'said face and bonded thereto, said combined metal and rubber spring acting to absorb forces acting parallel to the axis of fiexure vof said plate spring.

4. A flexible engine mount comprising a member secured to an engine to be supported anda member secured to a support for the engine, and a combined metal and rubber spring interposed between opposed surfaces of said members including a rubber'cushion having an axial passage therethrough and having a frustro-conical face confronting one of said surfaces and a frustro-conical plate spring conforming. to said face said combined metal and rubber spring acting to absorb forces exerted parallel'to the axis of flexure of said plate spring;

5. A iiexible engine mount comprising a. member secured to an engine to be supported and a' membersecured to a support for the engine, a combined metal and rubber spring interposed between 'opposed surfaces of said members including a rubber cushion and means for reducing the .stiifnessof said combined spring in compression ber secured to an engine to be supported and a member secured to a support for the engine, one of said members comprising ahollow separable housing having an aperture in one wall-thereof, a core assembly disposed in said housing having a; .stem smaller than said aperture extended through said aperture and carried by the otherof said members, said core assembly comprising a head portion on said stem, a rubber cushion bonded to each side'oi said head, and means for i'ncrveas` yingthe stiffnessv of said cushions Ialong their4 .l

major compressive axis over a portion of the load range comprising a conical plate spring bonded to the outer face of each of said cushions, said plate springs having their outer peripheries re-v ceived within the inner walls of said housing and positioning said assembly against lateral movement relative thereto.

7-. A iiexible engine mount comprising'a member secured to an engine to be supported and a member secured to a.l support for the engine, one o said members comprising a hollow separable housing having an aperture inv one wall thereof,

a'core assembly disposed in said housing having a. stem smaller than said aperture extended through said aperture and carried by the other rs inof said membersl said core assembly comprising a head portion on said stem, a rubber cushion bond, to each side of said head having an annular frustro-eonical outer face, and means for increasing the stiffness in compression of said cush` ions along their major compressive axis over portions ofthe load range which are below and above the normal working load ,range while maintain- Y ing the stiffness in compression substantially unchanged over said working load range which comprises va frustro-conical plate spring bonded to the outer face of each of said cushions, said plate springs having their Aouter peripheries received within' the inner walls of said housing and positioningsaid assembly against lateral movement relative thereto.

' 8. A resilient core unit for an engine mount in- 3 spring vbonded to a surface of said cushion which is transverse to said axis.

l prising a core member including a plate having cluding a resilient cushion,and means for increasing the stiffness of said cushion along its major compressive axis over a portion of the lload range comprising' a conical plate spring `bonded to a surface of said cushion which isV transverse to said axis.

9. A vresilient core unit foranVengine mount including a resilient cushion of rubber-like material, and means for increasing the stiffness' of said cushion along its majorcompressive axis over the portions of the load range which are above and below the normal working Vload range while maintaining the stiffness in compression along said axis substantially unchanged over said working loadrange comprising, a conical plate l a stem projecting from one face thereof, resilient cushions of rubber bonded to opposed faces of said plate, the cushion on the stem side of said plate having an aperture larger than the diameter of said stem and through which the latter extends, and frustro-conical plate springs bonded to the remote faces of said cushions.

12. A core assembly for an engine mount .coml 20 prising a core'member including a plate having a stem projecting from one face thereof, resilient cushions of rubber bonded to opposite faces of said plate, the cushion on the stem side of said plate having an axial aperture larger'than the diameter of said stem and through which the latter extends, the exposed ends of said cushions being dished to provide frustro-conical surfaces thereon, and frustro-conical plate springs conforming substantially to said faces in their unstressed condition and bonded to said surfaces.

ROBERT ELSBRE GORTON. 

